We're developing websites, and the live version has HSTS turned on. The test version however, does not. Firefox keeps complaining that HSTS is on whilst it's not. Opening the webpage in private mode works, but I'd like to clear the cache so I can use the website as usual. Things I've tried; - Clear history - "Forget this webpage" - Clear site data The website is not inside "SiteSecurityServiceState.txt" -- only the main site, not the subdomains. I've removed it anyways and it did not work.